PSC 135 Exam Notes PDF

Aristotle believed that the heart was the seat of the mind. Galen believed that the brain was the seat of the mind. Willis also believed that the brain was the seat of the mind and linked certain areas of the brain to certain functions(cerebral gyri=memory, brain stem=vital/involuntary functions, wa...

Aristotle believed that the heart was the seat of the mind. Galen believed that the brain was the seat of the mind. Willis also believed that the brain was the seat of the mind and linked certain areas of the brain to certain functions(cerebral gyri=memory, brain stem=vital/involuntary functions, was incorrect as to where did what) Gall believed that the shape of the skull could infer capabilities/size/shape of the brain(pseudoscience). Localization(aggregate field theory) belief that each area of the brain did different things Distributed processing belief that brain worked together to do everything. Ablation experiments ran by Flourens showed removal of cerebral hemispheres stopped all cognitive functions in dogs and pigeons. Broca proved cortical localization of function by visiting patient with loss of speech and showed damage to inferior frontal gyrus. Wernicke showed the superior temporal gyrus was involved in speech production. Broca and Werneckie established that cognitive abilities were linked to specific areas of the brain. Cajal mapped the first neuron by dying it and developed the neuron doctrine that the nervous system was made up of individual cells neurons carry out activity through synapses, synchronized activity. Berger did the first eeg study. Empiricists like Ebbinghaus performed experiments to understand mental processes. Rationalists like Wundt believed that the mind already had all knowledge available at birth and did self introspection. Behaviorists believed mind was unobservable(methodological) radical believes mind does not exist thinking is just subvocalization Law of effect behaviors that lead to good outcomes are likely to be repeated Three problems of the mind does exist, humans can create new rule based sentences, we can study mental processes with mris and stuff. Cognitive view Perception, attention, memory, language, thinking. Dendrites- get smaller as they move away from bod and receive messages from other neurons Nodes of Ranvier- short regions in axonal membrane not insulated by myelin sheath Ion channels- proteins that move ions across axon membrane Action potential- causes local changes in ion concentration and travels down axon to send messages Neurons are not physically connected to each other Neurotransmitters- submit information from one cell to the other by binding to receptors Synaptic cleft- gap between neurons Synapse- term for connection between neurons Presynaptic cell- neuron sends information down axon as electrical signal(action potential) Postsynaptic cell- neuron receives information from presynaptic cell Steps: Action potential travels down axon of presynaptic neuron Neurotransmitters released into synaptic cleft Neurotransmitter binds with receptors on postsynaptic neuron Ions flow into postsynaptic cells generating a postsynaptic potential Excitatory potential may cause action potential Inhibitory potential may prevent cell from firingResting membrane potential- voltage difference across membrane(at rest) Hyperpolarizing response- chemical transmission causes more negative potential Depolarizing response- chemical transmission causes more positive potential Threshold potential- level at which action potential is initiated Refractory period- 1ms where another action potential cannot be initiated All or nothing Chemical changes cause synaptic vesicles to bind with membrane Releases neurotransmitters to bind to proteins and releases ions Ion transfers can cause positive or negative potential Modulatory neurotransmitters: acetylcholine, Anything brain does dopamine, serotonin. Receptor type is what determines are if they are excitatory or inhibitory is caused by an action potential(underlying chemical process of brain). Direction terms: anterior/ventral=towards the front posterior/dorsal=towards the back superior=towards the top inferior=toward the bottom medial=toward the middle lateral= away from the middle rostral= toward the nose caudal=toward the tail Planes of section coronal= vertical line down the middle of the brain sagittal plane= across the brain horizontal= horizontal line of brain(parallel) Surface anatomy= gyrus(gyri) elevated ridges(can see), sulcus(sulci)= grooves in brain(cannot see) fissure= deep sulcus that separates brain Grey vs White matter= grey matter= cell bodies, dendrites, synapses cortex: outer layer of cerebrum nuclei: clusters of neurons in subcortical regions white matter: myelinated axons Brain structures: cerebellum: motor skills brain stem: connects brain to spinal cord cerebrum: made up of cerebral cortex(sulci and gyri) and subcortical structures seat of cognitive functions Four Lobes of Cerebral Cortex: front half of brain: output, speech, etc back half: input, perception, etc Frontal lobe: separated from temporal by lateral fissure and parietal by central sulcus, motor cortex, movement, where reasoning personality and social behavior occurs language production Parietal lobe: integration cortex, spatial awareness and navigation, perception Temporal lobe: auditory and high level cortex, process sensory input(esp audio) high level visual processing(faces), language comprehension Occipital lobe: visual processing, visual cortex Association cortex: integrates information across modalities loss of region can lead to agnosia where info cannot be integrated at higher levels Lateralization: contralateralization: opposite side, nervous system organized this way(opposite side gets info from the other side) ipsilaterial(same side)Topographic organization: areas of body represented by areas in the brain differents part of the body and face mapped together, close to each other space dedicated to body part determined by how Thalamus: relays sensory information to different brain regions besides smell, all goes to thalamus before sensitive it is going to other area also regulates conscious Hippocampus: memory, spatial recognition Amygdala: emotional response/regulation Basal ganglia: regulates motor movements, conditioning, emotion Cerebral cortex divided into two halves(left and right hemispheres): language in left hemisphere, both hemispheres connected by corpus callosum. if corpus callosum is cut you can multi task well but the visual fields flip Single unit recording: best temporal(~1 μs) and spatial(~10 μm), most expensive microelectrodes in the brain record action potentials of individual neurons by hovering outside, wired to oscilloscope which makes energy into clicking sound invasive but localized to one cell, animal studies, axon hillock=ideal EEGs: poor spatial excellent temporal(~1-5 ms) cheapest measures electrical activity in the brain by electrodes with gel, detects changes in voltage, good for understanding time of event, non invasive, poor spatial resolution but good temporal 32-64 electrodes ERP: patterns of EEG to time locked event, all eeg data averaged, all brain activity not associated with eeg gets canceled, positive=p negative=n, expected=p unexpected= n MRI: excellent spatial(~1 cubic mm) no temporal kind of costly shows brain structure, does not show time, magnetic field spins and realigns every atom of nucleus and makes 3d image, only structure of brain, does not show which is active, lesions become empty white spaces fMRI: great spacial(~2-3 cubic mm) bad temporal(~6 seconds) very expensive measures blood flow of oxygenated blood to brain shows where brain is active by where blood goes, localizes cognitive functions to brain regions Blood-Oxygen-Level Dependent is not very good because everything is recorded, Subtraction technique: subtracts normal brain activity during one cognitive state to another Brain activity during face viewing- brain activity during scrambled face viewing MEG:good spacial(~10 cubic mm) good temporal(Great (~10 ms) very very expensive, similar to EEG, uses magnetic fields produced by electrical activity, looks at tesla magnetic field measure, 200-300 electrodes, less distorted then EEG, used for time and location TMS high spatial and temporal resolution changing magnetic fields cause electrical currents in brain areas enhancing or disrupting activity, makes own magnetic field, studies relationships between brain and behavior, can manipulate brain activity Lesions: damage to specific area, occurs naturally mostly do to lack of blood supply, tissues not always dead may just be nonfunctional, gone forever once dead, heart attacks can cause lesions,, hippocampus most sensitive open head injuries(bullet) enter skull and cause lesions closed head injuries(car crashes) cause damage to many areas of the brain Lesion studies: single dissociation is when brain damage effects one function damage in one part of the brain can show what part of the brain does what however single dissociation is not conclusive and we cannot conclude they are all separate. if someone lost ability to understand speech they would lose ability to talk too. when one type of brain damage affects function A but not function B, but another type effects function B but not function A. Habit learning is distinct from memory, a=habit learning b= memory. can find what brain regions are used for what. natural invasive lesions in humans induced invasive lesions in animals. spatial resolution can vary, no temporal. low cost. some parts of the brain have high plasticity and can take role of area damaged by lesion.